"Logistically, we don't have to deal with rush hour traffic in the morning," Hite explained. "We're able to be not so much of a burden with the City of Dallas, especially on a downtown project where you have concrete trucks staged for literally five, six, seven hours at a time. We're less of an impact to them."

What's most remarkable about the overnight work is how fast special additives help the concrete harden. Twelve hours after it's poured, workers can walk on it.

They've built up to the eighth floor now, which is one-third of the 23-story structure.

The 1,000 room hotel is set to open in about two years. It's estimated to cost $550 million.